What's the best charity to donate to?

Donations typically spike as people reach into their wallets over the holidays. But before giving any money, consumers should see how their chosen charity is spending the money.

The Natural History Museum of Los Angeles County has earned a four-star rating, the highest possible, from CharityNavigator.com, a non-profit group that evaluates charities on how efficiently they're managed and how wisely they spend donations.

Senior Vice President Tom Jacobson says when the museum received three stars just two years ago, it was motivated to do better.

"We needed to look at our budget and see, 'Are we really spending more money on administration than we really should?' and we adjusted that slightly, so it makes us a better charity," Jacobson said.

Of the roughly 8,000 organizations followed by Charity Navigator, only about one in four get a four-star star rating. Many other charities are on shaky financial ground, faced with declining revenue and higher administrative costs.

That's the case with Aids Research Alliance in Los Angeles. The former four-star charity now gets just one star from Charity Navigator.

Charity Navigator CEO Ken Berger points to declining donations and higher-than-average expenses spent on fundraising.

"They have also got no rainy day fund, no savings. If they have any emergency or special need, they have virtually no money in the bank. If they have any cash flow problem, they're immediately in trouble," Berger said.

Aids Research Alliance conducts medical research and clinical trials. The non-profit's director says one reason donations are down is because people are living much longer with HIV.

"Funding has been cut at the government level, at the pharmaceutical level, donors stop donating," said Donn Montenegro with Aids Research Alliance.

Despite the drop in revenue and rating, Aids Research Alliance continues its quest to find a cure for AIDS.